An alternative to the Potassium manganate diffusion prac' please.

[Julie Delaney]

I need an easy alternative to the potassium manganate diffusion practical as we have 2 pregnant ladies in the department and this one is now classified as possibly causing harm to the unborn child; we don't want to take any chances. I don't really want to go down the starch/ iodine visking tubing one if possible. any ideas?
Thanks as always folks.

 

[GeorgetheScienceTech]

I need an easy alternative to the potassium manganate diffusion practical as we have 2 pregnant ladies in the department and this one is now classified as possibly causing harm to the unborn child; we don't want to take any chances. I don't really want to go down the starch/ iodine visking tubing one if possible. any ideas?
Thanks as always folks.

Substitute the Permanganate with Phenolpthalein. You're right not to take chanes.

 

[Julie Delaney]

Substitute the Permanganate with Phenolpthalein. You're right not to take chanes.

we don't have the solid, we only buy ready made liquid, we would have to use a slightly alkaline liquid though? surely?

 

[GeorgetheScienceTech]

we don't have the solid, we only buy ready made liquid, we would have to use a slightly alkaline liquid though? surely?

Yes Julie just over pH 8.2 (can be achieved by adding Sodium Carbonate or a Buffer, say pH 9.0)

 

[Julie Delaney]

Yes Julie just over pH 8.2 (can be achieved by adding Sodium Carbonate or a Buffer, say pH 9.0)

Thank you George.

 

[spud]

Would food colouring added to both hot and cold water do it?

 

[Helen Jones]

You can also show diffusion by putting a tea-bag in hot water, in a beaker. The colour shows up quite well, for the students to be able to see it moving through the water.

 

[Paul]

We do shark attack with red food colouring and hot cold and iced water

https://www.tes.com/teaching-resource/ks3-science-practical-investigations-part-1-6339323

 

[Lesley Newcombe]

We use a deodorant/perfume spray - squirt in the front of the class and get the pupils to raise their hands when they smell it!

 

[David Sait]

Would this diffusion practical using lead nitrate and potassium iodide be useful? https://edu.rsc.org/resources/diffusion-in-liquids/685.article

 

[Emil Tac]

Would this diffusion practical using lead nitrate and potassium iodide be useful? https://edu.rsc.org/resources/diffusion-in-liquids/685.article

That's a beautiful practical. We did this before. You can also do it with other salts that give insoluble precipitates. It not only demonstrates diffusion, but also shows that heavier ions diffuse slower which is something you don't get from the typical manganate practical.

 

[Peter Sigsworth]

I take it you just put a crystal in the corner of a cold beaker of water and another in a hot beaker of water (as per year 11 exploring science) and watch - in which case phenolpthalein wouldn't work - some solid food colouring instead of the permanganate - can get powdered form easily. But even if you can't get solid and have only liquid can use and syringe to place a few undiluted drops in the corner of the beaker.
If it's the diffusion in agar cubes then phenolphthalein is the recommended method.

 

[Peter Sigsworth]

Would this diffusion practical using lead nitrate and potassium iodide be useful? https://edu.rsc.org/resources/diffusion-in-liquids/685.article

I like this, thank you - will add to my lablogger templates

 

[Thowd Chap]

we use Marmite or Bovril ( love it or hate it ! ) , 1 spatula full in a beaker add hot or cold water and time how long it takes to dissolve.
Leave the spatula in the beaker as it is very sticky and hard to get off !

 

[Julie Delaney]

we use Marmite or Bovril ( love it or hate it ! ) , 1 spatula full in a beaker add hot or cold water and time how long it takes to dissolve.
Leave the spatula in the beaker as it is very sticky and hard to get off !

I would probably nick it for my toast!!

 

[Julie Delaney]

Would this diffusion practical using lead nitrate and potassium iodide be useful? https://edu.rsc.org/resources/diffusion-in-liquids/685.article

that's a great practical, but, again, not for our pregnant ladies as the lead salts may cause harm to the unborn child; also it's for our year 7 and 8's so not suitable for the youngsters. Much appreciated though!

 

[Jade]

Could you premake the permanganate melts? so they are not handling the permanganate directly.

 

[Jade]

Also if you are doing it as a diffusion prac rather than convention we've done methylene blue ice cubes before which work really well.

 

[megan l]

We've just started to show diffusion for KS3 with a tea bag in different temperatures of water, or with skittles and hot water on a plate or petri dish

 

[ChrisShan]

Tea bags in hot and cold water works very well